Tuna farms that are feeding Japan seen as a threat to natural stocks


Japan’s consumption of sliced raw tuna is undergoing a major upheaval as the surge in supply of farmed tuna brings down prices and threatens to decimate tuna stocks.

Representatives of the Turkish tuna-growing industry visited Japan at the end of last month and met with officials at the Fisheries Agency and environmental protection groups.

They said Turkey is adhering to international fishing rules and wants to press ahead with gathering data and conducting surveys on tuna resources in cooperation with Japan.

The visit took place after the Fisheries Agency said Turkish fishermen were probably seizing more tuna for fish husbandry than the amount set by an international organization, prompting some Japanese supermarkets to suspend the sale of Turkish-grown tuna.

Many people are critical of Japan’s “tuna economy,” which they say swallows up great quantities of natural marine resources.

It has opened the way for fishermen in other countries to catch young tuna and grow them in seawater ponds until they become big, fatty and ready to be shipped to Japan.

“Most (tuna grown in ponds overseas) are bound for Japan,” one fish farming industry insider remarked. “Dealers around the world are making desperate efforts to expand their (market) share here.”

Fishermen in other countries catch young tuna in masses and grow them in ponds. Sometimes they use small planes to locate a school of tuna and catch the entire lot with one throw of a net.

With the fish still in the net, they generally slowly pull the catch to huge ponds some 50 meters in diameter set up in the sea. They feed them sardines and other small fish until they become fatty.

Tuna farming started in Australia in the early 1990s and has since spread to Spain, Croatia, Malta and Mexico.

A Japanese businessman said consumers can now afford to eat good “toro” (oily bluefin tuna meat) at conveyor-belt sushi bars or buy it at supermarkets thanks to tuna farming, adding that consumers are definitely happy.

Japan imported about 3,000 tons of farmed tuna about 10 years ago, but last year the figure was believed around 35,000 tons. The increase has helped reduce the price of high-grade tuna from more than 5,000 yen per kg during the period of Japan’s bubble economy to less than 2,000 yen.

But while this is all good news for consumers, various problems have arisen.

Masanori Miyahara, director of the Fisheries Agency’s Coastal and Offshore Fisheries Division, said there is concern that the rapid expansion of fishery husbandry may have further complicated the control of tuna and deteriorated fish stocks.

Data provided by tuna growers show the volume of shipments, but not the number of fish actually caught. In addition, the flow of money and tuna is complex.

Citing an example, one industry source said a Spanish-funded company based in Libya used a Tunisian-registered ship to catch tuna and hauled the fish to ponds in Turkey, Greece and Malta.

They said fish husbandries are “data black holes” as virtually no figures on tuna growth or death rates have ever been made public.